The present invention relates to a metal probe adapted to be introduced into the lumen of an endoscope for use in intracorporeal lithotripsy, whereon a probe tip constituting a distal end of the probe being used for crushing calculi by shock waves which are transferred by means of the probe and which result from an impact energy transferred to the proximal end of the probe for transmission.
Metal probes of the aforementioned kind are used, for instance, in a lithotripter presenting a configuration in accordance with the European Patent EP 0 317 507 B1. In these lithotripters the impact energy transferred to the probe for transmission is obtained from the impact pulse produced by a pneumatically driven impact element on a probe head having an enlarged cross-section on the proximal end of the probe so that the resulting shock wave passing through the probe is used to achieve a uniform straight motion of the probe tip. This shock wave may be used for a process of intracorporeal crushing calculi such as nephroliths, uric acid calculi or cystoliths, which is performed by means of the employed endoscope.
The probes so far used, for instance, for crushing urethroliths comprise a comparatively blunt tip by which they hit on the calculus initially fixed by the uretral wall in a largely orthogonal direction. In this step it happens frequently that the calculus becomes detached from its fixation during the action of the shock waves and is tossed in a direction towards the kidney because in most cases the ureter is distinctly enlarged above the calculus under the action of the urine flowing in from the kidney. Therefore often the attempt is made to avoid such a calculus propulsion, which is undesirable for calculus crushing, by a supplementary fixation of the calculus, specifically by so-called xe2x80x9cbasketingxe2x80x9d wherein a basket-like calculus catcher, a so-called xe2x80x9cDormia basketxe2x80x9d, is additionally advanced into the ureter.
This calculus propulsion, which is hence inexpedient for the work with such probes and which can at most be counteracted with such expensive auxiliary provisions, is subject to another impairment to the extent of the ureteroscopes available for crushing urethroliths. In these ureteroscopes roughly half of the cross-section, which has a maximum width up to 4 mm (12 Charriere) on the distal end, is required for an operating duct receiving the probe whilst the other half of the cross-section receives a rigid rod-shaped optical system or also semi-rigid fibre glass filaments and bunches of individual optical fibres. This optical system, which is disposed laterally and hence not in the centre of the cross-section, dos not present a substantial wide-angle effect so that the tip of the probe advanced into the ureteroscope becomes visible only on the edge of the visual field along the uretral wall. Therefore mostly a slight tilt of the ureteroscope is required for placement of the probe tip onto the centre of the visible surface of the calculus. As a result, however, a variation of the direction of sight against the uretral wall is brought about. This effect is intensified by an inside bulging of the uretral wall which is not expanded between the urethrolith and the distal end of the ureteroscope, which bulging is always present, so that the tip of the probe and the calculus often disappear completely from the visual field and therefore a crushing of the calculus under sufficient visual control is often impossible.
The present invention is based on the problem of providing a metal probe of the type mentioned by way of introduction, which is suitable for intracorporeal lithotripsy and which allows for avoidance of a propulsion of the calculi relative to the joining ureter when calculi, specifically urethroliths, are crushed, and which should also allow, at the same time, for achievement of sight onto the calculus when a lithotripsy operation is performed by means of a conventional ureteroscope.
In accordance with the present invention this problem is solved in a metal probe of the general type defined by the introductory clause of Patent claim 1, by the provision that the tip of the probe is provided with at least one lateral notch near the probe end, which notch is configured for a laterally oriented fixation of a calculus to be crushed against a joining duct wall.
On account of the notch formed on the tip of the probe or expediently of a plurality of such notches along the tip of the probe, hence the possibility is achieved in the inventive metal probe to maintain a urethrolith, which is initially fixed against the uretral wall, in a continuously fixed position throughout the calculus crushing operation by the application of a slight lateral pressure via the probe onto the calculus so that, as a result, a propulsion of the calculus will be avoided during the calculus crushing operation. Due to the lateral arrangement of said one notch or several notches the advancing movement of the probe through the lumen of the ureteroscope remains, at the same time, unhindered and moreover the possibility is retained to perform an operation of calculus crushing in a manner so far common, using a probe end having a substantially blunt probe tip, wherein the tip of the probe is guided in a direction substantially orthogonal on the calculus rather than laterally against the calculus.
Further advantageous and expedient configurations of the inventive metal probe become apparent from the dependent claims.